O'Gara/elliott/Barrett/Joyce/ Crawley-Confusing O'Gara family

O'Gara/elliott/Barrett/Joyce/ Crawley-Confusing O'Gara family

I am searching for records or info on John & Catherine (Milarkey, Mularkey, Mullarky, Millarky???) O'Gara who emigrated to Fontenac, Ontario Canada sometime in the 1830's-to early 1840's. Marriage registry for John's son John says he's from Mayo, Ireland. Catherine (his sister) and what may be her gravestone reveals they were from Westport, Ireland. Any info on this family would be appreciated. Catherine married a James Elliott and John married Sarah Donoghue. Also looking for info on Mary & Bridget- both married Jeremiah Crawley in Canada. After Mary died Jeremiah married Bridget. Then there's this information I need to make sense of: 1859 Catherine O'Gara b abt 1835 marries David Barrett, b 1849 in Limerick. (Is this the Catherine who marries James Elliott? but see below there's also a surname of Joyce- 1860 - Ellen born in Kington 1860.1861 Canada Census shows two other children surname Joyce1864 - Catherine and David Barrett at baptism of her bro John's dau Catherine Ann.1880 US Census, he's shown married to Catherine's sister Margaret, b. July 1844, living in Cicero, IL.1916 - David's dc shows his parents are Mary Rice and David Barrett.Thank youEileen O'Gara Brosius